Hydrocarbon compositions containing the water-insoluble nitric acid oxidation product of naphthenic acids



United States Patent HYDROCARB'ON COMPOSITIONS CONTAINlNG THE W ATER-INSOIEUBILE NITRIC .ACID OXIDA- TION PRODUCT QF NAPHTHENICAIDS Peter B; 'Kelly, "College Station, "-Terr.,' assignor "to Gulf Research & DevelopmentCompany; Pittsburgh, Pa a corporation of Pennsylvania No.Drawing. Application March 15, 1956 ;SerialNo.'571;608

scnims. (CI. 44-72 This invention relates to antii-111stagents zfor hydrocarbon compositions and hydrocarbon compositions con- I,

can be introduced into'petroleum products through: faulty tankrclosures; Storage tanksrfor'petroleunfhydrocarbons because oftheir volatility :must .be constructed :to .allow room: for expansion and must be provided with: adequate breathing :devices. Thus, as the contents :of the tank contract, at night, for example, moist air is drawn in. The moisture thus drawnin condenses and settles to the bottomofthe tank, .The next. daytas thetank heatsup the.contents of the,tanl expand rthusjforcing ,out dried air. As this cycle --is repeatedday after day, appreciable :amountsof water are collected-in the bottom of the tank. Water contamination is particularly aproblem in. humid .atmospheres such as those encountered in the. tropics and ontheseaboardxas well as onboard ships. V

.In accordance with the present invention, a. hydrocarboncompositionis provided which gives prolonged protection against f rustingnormally resulting ,when metals .are exposed .to hydrocarbon compositions containing water. as. a; contaminant. I

lhave discovered that a hydrocarbon composition can belimproved withrespectto'its anti-rust characteristics A A p ,groperty' of'inhibitingthe rustingofi iron andst'eell urby incorporating in .said hydrocarbonjcomposition a .small amount of the-water-insoluble nitrogen-containing reaction product, obtained by'contactinga:naphthenic acid underoxidizing conditions with nitric acid. My invention, based'on this discovery, thus comprisesahydrocar- .bon composition containing ..an anti-rust improving amount of .the .vvater-in'soluble.v nitrogenecont-aining, reaction product; obtained by .contacting a .naphthenic acid under. oxidizing conditions with nitric acid;

The. hydrocarbon compositions. to which the anti-rust agent can be -:-added in accordancewith .the invention can vary; in volatility "from light gasoline to heavy oils and greases; Within this volatility-ranged intend to include diesel fuels, lubricating oils, slushing oils, turbine. oils, transformer oils, and the like.

' The gasolinecan be'a synthetic gasoline, a straight-rungasoline, :a cracked gaso line, 'or blends" thereof, and it can contain components 2,894,828 Patented .July 14, 1959 2 dro'forming, Platforming, or combinations of two more such processes.

' When thehydrocarbon,compositionito.which'the anti rust agentis added is gasolinethe gasoline can contain minorramounts of addition agents other than the antirust agent of the invention. Thus for example,the,gasoline can contain octane improving amounts oftetraethyl lead fluid. Other additionagents normally added to gasolines for a specificpurpose such as an anti-oxidant, a haze inhibitor, an oiliness agent, an anti-stalling agent, acorrosion inhibitor, alead scavenging agent, ajdye ,.etc., ,can beemp'loyed Without adversely affecting. the improved anti-rust characteristics derived in accordance witlrjthe invention.

When the hydrocarbon composition. to which theiantirust'agent added'is a lubricating oil the,oil canbepany oil having a viscosity within the range of common lubricating oils. The oil can be a syntheticoilor aminer'al oil including, refined. or semi-refined Paraffinic, .naphftheiiic or asphalt baseoilhaving a viscosity o'fabout to about 4000SUS at.10,0' F. If jclesired,,the anti-ru'stagent can be added toaiblend of oils ,of'suitable' viscositylinstea'd of a single oiliby meansof which any desired viscosity within the range of rSOrto 4000 SUS at 100 F. can be secured. a

When ,aflubricatingcomposition'pis desired the'lubricating oil canlcontain-m'inor amounts of, an addition agent other than the anti-rust I agent of thelinvention. Thus 'forex'amp'le, it is particularly advatageousfinmarryinstances to add an anti-,fo'am agentto the lubricatinglcomposition. Other addition agents normally added to I lubri: eating oils for a specific purposesuch as an anti-oxidant, pour point depressant, corrosion inhibitor, rviscos'itygindex improver, oiliness and extremepressure agent, and the like, ,can'be employed without adversely afiec ting the improved .anti-rust characteristics derived by the composition of this invention. "1

When a naphthenic acidIis oxidized'in thepresence, of a strong oxidant such as nitric acid, chromic acid or potassium permanganate, the resulting reaction rnass comprises a water-soluble portion anda waterainsoluble portion. The water-soluble portion comprises dibasic carboxylic acids. When nitric acidisused asthe oxidant, the water-'insoluhleportion comprises certainjnitrogencontaining hydrocarbons, the exact.structuralformulapf whichlhas notibeen completely determined. ,The nitrogen content-of the water-insoluble reactiompl'oductilthufs pounds" thus obtained when present ,in-, petroleum out at elevatedpressures in the order of ab obtained comprises about 3 .to. about 'GpercentbyIWeight of the reactionrproduct- The nitrogenjsubstituted com- .ca'rbons, even in exceedingly small amounts,'

" C. While'it'is preferredto carry out the reac, on

at atmospheric pressure, the reaction. canflalsobel c.

p P squ chs u Asrthep essure. raised the reaction temperature can correspondingly be raised The concentration of. the, nitric. acid "employed; in ,the oxidation of the naphthenic acid is not critical it should be" high; enough to. convert a subst of'the naphthenic acid toQa dib'asjic carhorgylic, a a n bl n of. t T s, th iconcentra'ti filqf the nitric acid can be. as lowas aboutBj) percent" ,1 as

hig as ab utiloof percent, although a mnpmmtmnpf abmt 70Perce1ltignerall Pr t red:

" cal, although an amount of-nitric acidin' excess oftliat theoretically required to oxidize the naphthenic acid in the charge to a 'dibas'ic carboxylic acid is preferred. In general, a ratio of at least about two parts, and preferably at least about four parts, of nitric, acid perpartof naphthenic acid is satisfactory. i

r The time requiredfor the substantial completion. of the reaction will depend, of course, upon the selection of variables defined hereinabove. Since the reaction is exothermic, from a practical point of view the time required will depend, to a large part, upon the rate at which heat produced can be removed from the reaction system. A period of at least about a hour and preferably about 1 to about 100 hours is generally satisfactory to convert a naphthenic acid to the corresponding dibasic carboxylic acid. Simultaneously with this reaction water-insoluble nitrogen-containing hydrocarbons are formed. It is the latter products with which this invention is concerned;

V The naphthenic acids which can be employed'as the starting" material to produce water-Soluble dib'asic acids and water insoluble nitrogen-containing products can be defined as cycloparaflinic compoundskontaining at least one carboxylic acid group per molecule, particularly those whose boiling points, range fromabout 390 .to about 660 F., and whose molecular weights are about 128 to about 480. As charge stock. in producing the useful additive for the invention, any of the naphthenic acids defined above or mixtures of such naphthenic acids can be employed. Preferably, the charge stock consists almost solely of naphthenicacids, although minor amounts of other closely associated compounds or materials which do not adversely afiect the course of the oxidation reaction can be present. Included among the naphthenic acids which are suitable starting materials in producing the water-insoluble product for use in the invention are methylcyclopentane carboxylic acid, dimethylcyclopentane carboxylic acid, methylcyclohexyl carboxylic acid, methylcyclohexyl acetic acid, etc. Commerially available mixtures of naphthenic acids can be used in accordance with the invention. Of the commercially available naphthenic acids, I prefer the C to C acids. However,higher molecular weight acids, i.e., those containing more than 12 carbon atoms including those having double naphthenic rings can be used. i

The oxidizing action necessary. to produce appreciable yields of water-soluble dibasic acids and water-insoluble nitrogen-containing compounds must be strong and therefore mere air blowing will not suflice, although an oxygen-containing gas such as air incombination with nitric acid can be employed to reduce the consumption of nitric acid. In such a case an amount of air to give 100 percent by weight of molecular oxygen based upon the nitric acid can be employed. v-Wliile any strong oxidant can be used where the sole desired product is a dibasic carboxylic acid; only, (nitric acid can be used to give the. desired water-insoluble nitrogen-containing compound, employed in accordance with this invention. The oxidationbf naphthenic acids to produce the water-insoluble nitrogencontaining product employed inaccordance with the invention can be conducted with or without the aid of an oxidation-promoting catalyst. Included among the oxidation-promoting catalysts which .can be used are ainmonium metavanadatefpotassium permanganate and co- .balt nitrate.

The optimum amount of reactionproductemployed in any given material will vary somewhatdepending upon the particular hydrocarbon composition employed and upon the severity of the r'ustrinducing conditions encountered. The amount of thewaterrinsoluble nitrogen-containing reaction productemployed in a liquid hydrocarbon composition can comprise about 1 to about '20 pounds per thousand barrels of hydrocarbon. .When. the hydrocarbon composition is gasoline, I have. obtained'highly satisfactory anti-rust characteristics when the'water-insoluble nitrogen-containing reaction product was employed in same? at f m .1945 Page h usa d. a rels- In any event, I employ an amount of the water-insoluble nitrogen-containing reaction product suflicient to inhibit or substantially prevent therusting of ferrous metal surfaces normally encountered when the hydrocarbon composition contains no such reaction product. I have found that the incorporation o'f'this' reaction product in gasoline in amounts offrom 5, to15 pounds per thousand-barrels has no deleterious affect on the other desirable characteristics of the fuel.

The following examples will illustrate the preparation of compounds useful in my invention.

Four hundred gramsef petroleum naphthenic acids having a boiling range of about to about C. at 2.5 mm. of Hg and a molecular weight of 220 was added dropwise to 1600' ml. of 70 percent nitric acid containing one gram of ammonium metavanada'te. The mixture thus formed was stirred and heated to. 85 C. This temperature was maintained (i5 C.) until substantially all of the hydrocarbon layer had disappeared. The reaction :mixturetwas thencooled whereupon the mixture formed a hydrocarbon layer and an aqueous layer. The aqueous layer containing a substantial portion of the nitricuacidwasremoved andfurther processed to recoverpolybasic acids. The-hydrocarbon layer was dissolved in twice its volume of benzene and then washed with .water until the water used for washing was colorless. The benzene layer was then dried over calcium chloride andthebenzene removed by vacuum distillation. The product thus obtained'was the water-insoluble nitrogencontaining product useful as an anti-rust agent according to my invention. Theproduct was. a clear, reddishfoil with a disagreeablemdor. This product hadxa: carbonyl number of 90.3, a saponification number of 4l0and a molecular weight of 226. The oxidized product contained 58.76 percentcarbon, 7.95 percent hydrogen, 5.47 percent nitrogen and 24.82 percent oxygen (by difierence) EXAMPLE 2 .Fifty grams of petroleum naphthenic acids having a boiling range ofabout 50? to about"f C. at 2 mm. of Hg and a neutralization value of 158 was oxidized as in Example 1 using 200 ml. of 35 percent nitricacid containing 9.2 gram of ammonium metavanadate. The product obtained after heating the mixture at 85 C. as in Example 1 consisted of two layers which were separated by decantation. The lower aqueouslayer was further processed to recover polybasic acids. ,The hydro carbon layer was dissolvedin toluene andfthen washed with water until the wash 'waterj was colorless. The toluene .layer was then dried overcalcium'chloride and the toluene removed by vacuum distillation. The dried product thus obtained was fthe. water-insoluble nitrogencontaining product useful as an anti-rust agent according to my invention. This product had a neutralization value of 14l anda nitrogen-content of 3.4 perceu t.

.a gasolinehas beencompared with afgasoline containing no anti-rust agent, with a gasoline; containing a commercially available anti-rustagent, and with a g'asoline containing unoxidizedj na'phth'enic acids. 'The unoxidized naphthenic acids used for comparison were those used in preparing the watrdnsoluble"nitrogen containing reaction product: of. Example 1. r The comparison was made by placing 6]"1: SAE ,1020, sand bla'sted, "solvent rinsedsteel strips in contact with mixturesrof water and gasoline for prolonged periods of time. The steel strips we e ene m ned GIm -I ma n m ing the determinations, 400 m1. ofga solin'e and 100 ml. of distilled water were placed in a glass container. Steel t s er vala l a: he 9......FHQE therm- 9 as agsegsae strip was in the water layer, "anotherpart in the gasoline layer, and a further part inthe airl space above the liquid. The container was tightly. sealed-and then violently agitated for: about 1 minute. The container was then stored in;v the dark at room temperaturewithout further agitation. Steel strips were removed from the container at diiferent intervals to determine the: amount of rust formed on thervarious segments. Steel specimens which were completely free from rust were given an anti-rust rating of 100. Steel strips which were completely covered with rust were given an anti-rust rating of zero.

Table I summarizes the results obtained with gasoline containing various additives in concentrations as shown.

The improved results obtained in accordance with my invention are apparent from the summary of data in Table I. It will be noted that the base gasoline and the gasoline containing naphthenic acids gave very little protection against rusting. However, the nitric acid oxidation product of Example 1 gave prolonged protection at concentrations of 5 to 15 pounds per thousand barrels of gasoline. The protection thus obtained was greater than that obtained with the commercially available additive in concentrations of and pounds per thousand barrels of gasoline.

The physical characteristics of gasoline are not sub stantially changed by the addition of the water-insoluble nitric acid oxidation product as evidenced by the following data.

It will be noted that the oxygen stability of the gasoline is improved but that otherwise there is very little effect on the physical characteristics of the gasoline. While there appears to be a slight increase in the existent gum and in the copper dish gum, the increase is not actual gum formation but is due to the additive itself, which being non-volatile, remains as a residue when the gasoline is evaporated. In each instance, the additive amounts to about 2.8 mg. per 100 ml. of gasoline.

While my invention is described above with reference to various specific examples and embodiments, it will be understood that 'theinvention is not limited to such ex-- amples and embodiments andmay-be variously practiced within the scope of the claims hereinafter made.

I claim:

1. A hydrocarbon composition comprising a major amount of a normally liquid hydrocarbon'normally tending to rust" ferrous metals when contaminated with water and a small amount; suflicient to substantially retardsuch rusting, of the water-insoluble nitrogen containing reaction product obtained by oxidizing at about 70 to about 150 C. one part by weight of a naphthenic acid having a boiling range of about 390 to about 660 F. at atmospheric pressure and a molecular weight of about 128 to about 480 in the presence of at least two parts by Weight of nitric acid having a concentration of about 30 to about 100 percent, the oxidizing period being suflicient to produce a water-soluble dibasic carboxylic acid and said water-insoluble nitrogen-containing reaction product.

2. A hydrocarbon composition comprising a major amount of a normally liquid hydrocarbon normally tending to rust ferrous metals when contaminated with Water and a small amount, sufficient to substantially retard such rusting, of the water-insoluble nitrogen-containing reaction product obtained by oxidizing at about 70 to about 150 C. one part by weight of a naphthenic acid having a boiling range of about 390 to about 660 F. at atmospheric pressure and a molecular weight of about 128 to about 480 in the presence of at least two parts by weight of nitric acid having a concentration of about 30 to about 100 percent, the oxidizing period being sufficient to produce a water-soluble dibasic carboxylic acid and said water-insoluble nitrogen-containing reaction product, the nitrogen content of said Water-insoluble nitrogen-containing reaction product comprising about 3 to about 6 percent by weight of the reaction product.

3. A hydrocarbon composition having improved antirust characteristics which comprises a normally liquid hydrocarbon and about 1 to about 20 pounds per thousand barrels of said normally liquid hydrocarbon of the waterinsoluble nitrogen-containing reaction product obtained by oxidizing at about 70 to about 150 C. one part by Weight of a naphthenic acid having a boiling range of about 390 to about 660 F. at atmospheric pressure and a molecular weight of about 128 to about 480 in the presence of at least two parts by weight of nitric acid having a concentrationof about 30 to about 100 percent, the oxidizing period being sufficient to produce a water-soluble dibasic carboxylic acid and said waterinsoluble nitrogemcontaining reaction product, the nitrogen content of said water-insoluble nitrogen-containing reaction product comp-rising about 3 to about 6 percent by weight of the reaction product.

4. A motor fuel having improved anti-rust characteristics which comprises a major amount of gasoline and about 5 to about 15 pounds per thousand barrels of gasoline of the water-insoluble nitrogen-containing reaction product obtained by oxidizing at about 70 to about 15 0 C. one part by weight of a naphthenic acid having a boiling range of about 390 to about 660 F. at atmospheric pressure and a molecular weight of about 128 to about 480 in the presence of at least two parts by weight of nitric acid having a concentration of about 30 to about 100 percent, the oxidizing period being sutficient to produce a water-soluble dibasic carboxylic acid and said waterinsoluble nitrogen-containing reaction product, the nitrogen content of said water-insoluble nitrogen-containing reaction product comprising about 3 to about 6 percent by weight of the reaction product.

5. A motor fuel having improved anti-rust characteristics which comprises a major amount of gasoline and about 5 to about 15 pounds per thousand barrels of gasoline of the water-insoluble nitrogen-containing reaction product obtained by oxidizing at about to about C. one part by weight of petroleum naphthenic acids, having a boiling range of to C. at 2.5 mm. of

Hg and a molecular weight of 1 about 220, in the presence of at least two parts by weight of nitric acid having a concentration of 70 percent and ammonium metavanadate, the oxidizing period being sufiicient to produce a watersoluble dibasic oarboxylic acid and said water-insoluble nitrogen-containing reaction product, the nitrogen content of said water-insoluble nitrogen-containing reaction product comprising about 5.5 percent by weight of the reaction product.

References Cited in the file of this patent UNITED STATES PATENTS Cannichael et a1; Apr. 2, 1940 Wasson et a1; June 11, 1946 Coe et a1. Aug. 9, 1949 FOREIGN PATENTS Germany Nov. 11,1943 

1. A HYDROCARBON COMPOSITION COMPRISING A MAJOR AMOUNT OF A NORMALLY LIQUID HYDROACARBON NORMALLY TENDING TO RUST FERROUS METALS WHEN CONTAMINATED WITH WATER AND A SMALL AMOUNT, SUFFICIENT OT SUBSTANTIALLY RETARE SUCH RUSTING, OF THE WATER-INSOLUBLE NITROGEN-CONTAINING REACTION PRODUCT OBTAINED BY OXIDIZING AT ABOUT 70*F. TO ABOUT 150*C. ONE PART BY WEIGHT OF A NAPHTHENIC ACID HAVING A BOILING RANGE OF ABOUT 390* TO ABOUT 660*F. AT ATMOSPHERIC PRESSUR AND A MOLECULAR WEIGHT OF ABOUT 128 TO ABOUT 480 IN THE PRESENCE OF AT LEAST TWO PARTS BY WEIGHT OF NITRIC ACID HAVING A CONCENTRATION OF ABOUT 30 TO ABOUT 100 PERCENT, THE OXIDIZING PERIOD BEING SUFFICIENT TO PRODUCE A WATER-SOLUBLE DIBASIC CASRBOXYLIC ACID AND SAID WATER-INSOLBLE NITROGEN-CONTAINING REACTION PRODUCT. 